into today's Mid-Continent Tower), Atlas Life Building, Holy Family Cathedral, Holy Trinity Greek Orthodox Church, and the Mayo Hotel. Known for a time as "Terra Cotta City", Tulsa hosted the International Sixth Congress on Art Deco in 2001. The core downtown area was designated on the National Register of Historic Places as the Oil Capital Historic District in 2010. Downtown Tulsa is in the northwest quadrant of the city and is ringed by an expressway called the Inner Dispersal Loop. Downtown's buildings include many large office towers. At , the BOK Tower (formerly One Williams Center) was the tallest building in any of the 5 "plains states" (Oklahoma, Kansas, Nebraska, North Dakota and South Dakota) until the Devon Tower in Oklahoma City was completed in 2012. The BOK Tower was designed in 1975 by Minoru Yamasaki & Associates, the same architect who designed the World Trade Center in New York City. The Tulsa Performing Arts Center occupies a half city block in Tulsa's historical downtown. The PAC is also the design of Minoru Yamasaki. It houses five theatres and a reception hall. More than a quarter of a million people visit the Center each year to attend a performance from one of Tulsa's seven acclaimed musical and dramatic companies including the Tulsa Ballet, Tulsa Symphony Orchestra, Tulsa Opera, Theatre Tulsa, and a variety of symphonic groups. The PAC hosts a multitude of cultural events through the fall, winter and spring. In 2005 the City of Tulsa broke ground on a 19,199 seat regional events center designed by architect César Pelli. The arena was named the BOK Center (or Bank of Oklahoma Center) and opened on August 30, 2008. Blue Dome District Another popular downtown entertainment district is the Blue Dome, named for a distinctive, domed building at Second Street and Elgin Avenue, in the area in the eastern section of downtown. The building was originally constructed in 1924 as a Gulf Oil service station. It has been converted to an information desk/office for the district, and is about two blocks south of the OneOK field. East Village East Village comprises 115 acres bordered by East 2nd and East 7th Streets, Detroit Avenue and Lansing Avenue, just inside the inner-dispersal loop. This area boasts an upscale martini bar, American Theatre Company Studios, a hair salon, a pet day care, photography studios, lofts, a knitting room and living arts district, among others.